Fouling
Coking (process fouling)
Also known as coke deposition, cracking-furnace coking.
Coking in refining and petrochemicals is the formation of hard carbonaceous deposits on hot process surfaces — typically inside ethylene-cracker furnace tubes, delayed-coker drums, and the radiant tubes of fired heaters. Coke forms by thermal cracking of hydrocarbons in stagnant or low-velocity zones, accumulating until a planned decoking outage removes it.
Where it dominates
- Ethylene-cracker furnace radiant tubes
- Visbreaker furnaces
- Delayed-coker process drums
- Some refinery heater tubes
- FCC catalyst (different mechanism — burned off in the regenerator)
Cleaning
Coke is hard, bonded, and refractory — far beyond what sonic horns can address. Standard cleaning is by decoking: a campaign in which the heater is run with a steam-air mixture at elevated temperature, oxidising the deposit out of the tubes. Manual mechanical pigging is sometimes used on selected sections.
Acoustic cleaning is not a primary tool against coking, but downstream particulate-handling equipment (decoking-effluent dust collection, SRU adjacency) can benefit from sonic-horn coverage.
Related terms
Related terms
- Fluid catalytic crackingFluid catalytic cracking (FCC) cracks heavy hydrocarbons into gasoline and lighter products over a fluidised catalyst bed. The associated regenerator and separators benefit from sonic-horn cleaning.
- Reformer furnaceA reformer furnace produces hydrogen by reacting natural gas with steam over a nickel catalyst at high temperature. Convection-section ammonium-salt fouling is the principal cleaning concern.
- Fouling (general)Fouling is the accumulation of unwanted deposits on process-equipment surfaces. The general umbrella term covering slagging, scaling, coking, sintering and many other specific mechanisms.